1. Field of the Invention
The subject invention relates to magnetic actuation methods and apparatus, to magnetic actuators, and to optical apparatus, including optical shutters.
2. Disclosure Statement
This disclosure statement is made pursuant to the duty of disclosure imposed by law and formulated in 37 CFR 1.56(a). No representation is hereby made that information thus disclosed in fact constitutes prior art, inasmuch as 37 CFR 1.56(a) relies on a materiality concept which depends on uncertain and inevitably subjective elements of substantial likelihood and reasonableness, and inasmuch as a growing attitude appears to require citation of material which might lead to a discovery of pertinent material though not necessarily being of itself pertinent. Also, the following comments contain conclusions and observations which have only been drawn or become apparent after conception of the subject invention or which contrast the subject invention or its merits against the background of developments subsequent in time or priority.
Despite its old age, the art of magnetic actuators has not been able to satisfy certain needs by conventional means. Reference may in this respect be had to U.S. Pat. No. 1,552,676, by R. E. H. Carpenter et al., issued Sept. 8, 1925 and U.S. Pat. No. 2,872,546, by S. K. Babcock, issued Feb. 3, 1959. These two expired patents show magnetic actuators or relays having a movable armature pivoted between opposite pole pieces. In practice, those proposals entailed considerable effort in the design and provision of the requisite pivot structure and made for a relatively complex and generally impractical construction, aggravated by the need of a cumbersome and time-consuming assembly procedure.
More or less related developments offered no alleviating solution, as may be seen from U.S. Pat. No. 1,792,318, by T. J. O'Meara et al., issued Feb. 10, 1931, and showing an electromagnetic apparatus of the railway signaling type, U.S. Pat. No. 3,156,798, by H. T. Rights, issued Nov. 10, 1964 and showing resonant frequency reed relays, U.S. Pat. No. 3,609,608, by F. J. Pokorny, issued Sept. 28, 1971 and showing a magnetic latch for circuit interruptors, and U.S. Pat. No. 3,745,495, by H. D. Chay et al., issued July 10, 1973, and showing a magnetic actuator comprising a core structure having two distinct magnetic flux paths including a movable armature.
In the area of electromagnetically actuated optical shutters, solenoids have been employed to release manually cocked shutters or to open a shutter closed by springs. In the former case, the need for manual operation presents an inconvenience. In the latter case, a large moving mass is present, together with a relatively complex leverage mechanism.
In the advertising display art, oppositely poled, pivoted magnets have been employed at a distance from an electromagnet in order to flip over a sign or sign element at will. That arrangement would, however, not be suitable for positive actuation purposes and would not develop sufficient power for high-speed actuation.